It is well known to direct a stream of water upon a target for many purposes including, for example, cooling, cleaning, and fire extinguishing. In fire extinguishing, water is typically supplied to a nozzle from a main or other source through a hose or other conduit interconnecting the two. A single hose is ordinarily adequate to supply relatively small flows of water, less than about 2000 l/min, to either handlines or to mechanically restrained nozzles. Those mechanically restrained nozzles are commonly referred to as monitors, and ordinarily are arranged with swivel joints allowing both vertical and horizontal nozzle travel.
Very great water flows are required to successfully fight large petroleum and chemical fires; particularly fires in large, liquid petroleum storage tanks. Present standards suggest the need for monitors with a capacity in the range of 7,500 to 25,000 l/min to fight such fires. It ranges from impracticable to impossible to supply that level of flow to a portable monitor through a single hose. Consequently, high capacity monitors employ a manifold arrangement allowing for the connection of two, three, or even more, water lines to a single monitor. The manifold arrangement typically comprises a two-way or three-way, Siamese-type fitting with clapper valves to prevent backflow.
The range, or throw distance, of a monitor is of considerable importance in fighting fires. That is particularly true in those instances in which a foam concentrate is added to the water stream thrown by the monitor. When using conventional monitors and aspirating nozzles, it is usual to experience a substantial decrease in throw distance using foam as compared to plain water. Yet, the need for maximizing the throw distance is ordinarily most critical when applying foam.
The range of any monitor/nozzle system, throwing either water or foam, is determined primarily by how efficiently the system converts pressure energy to water velocity (kinetic energy), and by how effectively the nozzle shapes the issuing water (or water-foam) stream so that it does not break apart in the air. A lot of attention has been paid to nozzle design, but little concern has been shown for minimizing turbulence losses while combining different water streams. In fact, the magnitude of such losses appears to be totally unappreciated in the art.
It is evident that improvements in the means used to merge liquid streams, so as to reduce frictional and turbulence losses, will directly translate to increased velocity of the exiting stream. That, in turn, results in an increased throw distance for monitor/nozzle systems and an increased capacity as well. Such improvements in performance are clearly of substantial importance in the art.